Extensible Data Provider Querying and Scheduling System

ABSTRACT

Embodiments present a common access mechanism that can be used by one or more applications to access different data sources in a storage layer and have data stored in the data sources returned to the one or more applications. The common access mechanism can be presented by a data model that is implemented by a query and aggregation layer of an extensible querying/scheduling system. At least some individual data sources store data in different formats and have their own specific access mechanisms of which the one or more applications are unaware. In embodiments, the data model creates one or more data providers that are individually associated with individual data sources and knowledgeable of how to access data stored in an associated data source. At least some of the data providers receive queries for data and execute the queries using a different thread than the data model. At least some of the data providers are creatable on a thread that is a same thread as the data model.

RELATED APPLICATIONS

This application is a continuation of, and claims priority to U.S.patent application Ser. No. 13/355,170, filed on Jan. 20, 2012, which isa continuation of and claims priority to U.S. Pat. No. 8,122,000, filedon Dec. 3, 2010, which is a continuation of and claims priority to U.S.Pat. No. 7,849,067, filed on Jan. 31, 2008, the disclosures of which areincorporated by reference herein.

BACKGROUND

In application contexts, such as Web browser contexts, data that isutilized by an application can be stored in various locations. Forexample, in Web browser contexts, “data” can refer to local sources ofuser data such as history URLs and/or external sources of data such assearch results from third party search providers. In addition, differentdata sources can store data in different formats. Different data sourcescan utilize different data access mechanisms which can complicatematters when an application wishes to retrieve and use data fromdifferent data sources. Further complications can exist when datacomprises different types of data, such as that which is stored indifferent formats. For example, individual data sources can typicallyhave their own specific associated set of application program interfaces(APIs). This means that an application should be knowledgeable of eachof the individual APIs in order to retrieve and utilize data fromdifferent data sources.

In the environment of different data sources and different types ofdata, it is difficult to access collections of data from differentsources. Additionally, it is difficult to seamlessly add new datasources that are to be used by an application because the new datasources may employ access mechanisms that are unknown to an application.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter.

Various embodiments provide an independent layer between an applicationuser interface and various data sources so that both the user interfaceand data sources can be added to, removed, or modified without affectingthe other. The independent layer provides scalability to allow datasources and data providers to be plugged into a system in an easymanner.

In one or more embodiments, the independent layer provides a common setof query APIs that can be used by client applications to make queries onone or more data sources. The independent layer then communicates thequeries to one or more data providers associated with individual datasources. Queries are executed on the data sources and results arereturned back up through the data providers and independent layer forconsumption by a client application. In at least some embodiments, theclient application comprises a Web browser that makes use of theindependent layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The same numbers are used throughout the drawings to reference likefeatures.

FIG. 1 illustrates a system in which various principles described hereincan be employed in accordance with one or more embodiments.

FIG. 2 illustrates an example system in accordance with one or moreembodiments.

FIG. 3 illustrates an example system in accordance with one or moreembodiments.

FIG. 4 is a flow diagram that describes steps in a method in accordancewith one or more embodiments.

FIG. 5 illustrates an example system in accordance with one or moreembodiments.

FIG. 6 illustrates an example data layer diagram in accordance with oneor more embodiments.

FIG. 7 illustrates an example system that can be used to implement oneor more embodiments.

DETAILED DESCRIPTION

Overview

Various embodiments provide an independent layer between an applicationuser interface and various data sources so that both the user interfaceand data sources can be added to, removed, or modified without affectingthe other. The independent layer provides scalability to allow datasources and data providers to be plugged into a system in an easymanner.

In one or more embodiments, the independent layer provides a common setof query APIs that can be used by client applications to make queries onone or more data sources. The independent layer then communicates thequeries to one or more data providers associated with individual datasources. Queries are executed on the data sources and results arereturned back up through the data providers and independent layer forconsumption by a client application. In at least some embodiments, theclient application comprises a Web browser that makes use of theindependent layer.

In the discussion that follows, a section entitled “OperatingEnvironment” is provided and describes one environment in which one ormore embodiments can be employed. Following this, a section entitled“Example Embodiment—General” is provided and describes a generaloverview of example embodiment. Next, a section entitled “ExampleEmbodiment with Indexing Mechanism—General” is provided and describes anexample embodiment that utilizes an indexing mechanism in accordancewith one or more embodiments. Following this, a section entitled“Example Method” is provided and describes an example method inaccordance with one or more embodiments. Next, a section entitled“Example Web Browser Embodiment—Implementation Example” describes animplementation example in the Web browser context in accordance with oneor more embodiments. Last, a section entitled “Example System” isprovided and describes a system that can be utilized to implement one ormore embodiments.

Operating Environment

FIG. 1 illustrates an operating environment in accordance with one ormore embodiments, generally at 100. Environment 100 includes a computingdevice 102 having one or more processors 104, one or morecomputer-readable media 106 and one or more applications 108 that resideon the computer-readable media and which are executable by theprocessor(s). The computer-readable media can include, by way of exampleand not limitation, all forms of volatile and non-volatile memory and/orstorage media that are typically associated with a computing device.Such media can include ROM, RAM, flash memory, hard disk, removablemedia and the like. One specific example of a computing device is shownand described below in FIG. 7.

In addition, computing device 102 includes a software application in theform of a Web browser 110. Any suitable Web browser can be used examplesof which are available from the assignee of this document and others. Inaddition, an independent layer in the form of a querying/schedulingsystem 111 is provided and serves to interface between applications 108,Web browser 110, and a plurality of data sources comprising local datasources 113 and/or remote data sources 115. In addition, environment 100includes a network 112, such as the Internet, and one or more web sites114 from and to which content can be received and sent.

In at least some embodiments, applications 108 and/or Web browser 110are configured to utilize the querying/scheduling system 111 to accessthe various data sources. These data sources can and typically do storedata in different formats and can have their own specific accessmechanisms of which an application or Web browser is unaware.

In one or more embodiments, querying/scheduling system 111 presents acommon set of querying APIs as well as other APIs that can be used byapplications to access data that is stored in the various data stores.By providing a standardized or common set of querying APIs, various datasources can be plugged into the system without requiring theapplications to be specifically knowledgeable about the accessmechanisms that are used to access stored data.

Computing device 102 can be embodied as any suitable computing devicesuch as, by way of example and not limitation, a desktop computer, aportable computer, a handheld computer such as a personal digitalassistants (PDA), cell phone, and the like.

Example Embodiment—General

FIG. 2 illustrates a system in accordance with one embodiment generallyat 200. In this example, system 200 includes an application 202, aquerying/scheduling system 111 which includes a data model 204 and aplurality of data providers 206, 208, and 210. Multiple different datasources are provided at 212, 214, and 216. In this particular example,individual data providers are associated with individual data sources.So, for example, in the illustration, data provider 206 is associatedwith data source 212, data provider 208 is associated with data source214, and data provider 210 is associated with data source 216. In theillustrated and described embodiment, the data sources can comprisedifferent types of data sources each with their own particular dataaccess nuances. The individual associated data providers areknowledgeable of the data access nuances, such as any specializedinterfaces or access requirements, and can access and query theirassociated data source. As such, the data providers can be said to wrapan associated data source.

In at least some embodiments, the data providers are COM components thatcan be co-created by the data model. The data providers can be createdon the same thread as the data model. Alternately or additionally, thedata providers can be created on a worker or background thread forreasons that are discussed below. As will be appreciated, the dataproviders need not, however, be COM components. As such, other types ofcomponents can be used without departing from the spirit and scope ofthe claimed subject matter.

In operation, application 202 exposes an interface 202 a whichessentially provides a callback interface that can be used to returnsearch results through a Notify( ) method that can be called. Data model204 exposes an interface 204 a that includes various methods that can becalled to conduct searches and return search results. To this end, andin this example, interface 204 a includes a Query( ) method, a Cancel( )method, and a Notify( ) method.

The individual data providers 206, 208, and 210 respectively expose aninterface 206 a, 208 a, and 210 a. The individual interfaces include aQuery( ) method that can be used to query an associated data source.

When application 202 issues a query, it provides a number of parametersand calls the Query( ) method on the data model 204. In one or moreembodiments, the application's call to the data model's Query( ) methodis an asynchronous call. In one or more other embodiments, this call canbe synchronous. By way of example and not limitation, the parametersincluded in the application's call can include one or more of a list ofclass IDs associated with the individual data providers that are desiredto be queried, the subject of the query such as any query text or otherdata that might be utilized in the query, a number of desired results,properties of the data that is to be returned, a sort order or relevancyorder, and/or a data model callback which serves as a pointer tointerface 202 a. The data model's Cancel( ) method can be used to cancela query and receives as a parameter a query ID described just below.

When the data model 204 receives the query from application 202, itproduces a query ID that it returns to the application 202. A query IDidentifies the query for subsequent reference by the application. Thedata model 204 receives the query and, in turn, ascertains, from theincluded class IDs, which of the data providers are to be queried. Thedata model 204 then generates appropriate queries for the data providersand then calls the associated providers' Query( ) method. The individualdata providers receive the queries and execute them on their associateddata sources. Query results are then returned back up through the datamodel by calling its Notify( ) method and passing in a list of searchresults. In turn, the data model 204 calls the application's Notify( )method passing in the returned search results. The application can thenuse the search results in any suitable way such as by presenting thesearch results in a suitable user interface. It is to be appreciated andunderstood that the returned search results can come from one or both oflocal data sources, such as those illustrated, or remote data sources,such as those shown in FIG. 1.

In this system, the querying/scheduling system is extensible so that newdata providers or new data sources can be easily plugged in. By virtueof exposing a common set of APIs to various applications, the data modelabstracts away the specific nuances that are utilized to access andquery the various data sources. In addition, the common set of APIs alsoabstracts data providers for applications, such as a browser. In thismanner, applications can access new data sources without having to beknowledgeable of the specifics of how access takes place. Rather, anassociated data provider that is knowledgeable of new data sources canbe plugged into the system and used by the data model to access andconsume data from an associated data source.

Example Embodiment with Indexing Mechanism—General

FIG. 3 illustrates a system in accordance with one embodiment generallyat 300. Like numerals from the FIG. 2 embodiment are utilized to depictlike components. In this example, system 300 includes an application202, a querying/scheduling system 111 which includes a data model 204and a plurality of data providers 206, 208, and 210. In this particularexample, an indexing mechanism 302 is provided and serves as an indexinto multiple different data sources such as those provided at 212, 214,and 216. In one or more embodiments, the indexing mechanism can beextensible so that other indexing mechanisms can be added. In thisparticular example, individual data providers are associated withindividual data sources. So, for example, in the illustration, dataprovider 206 is associated with data source 212, data provider 208 isassociated with data source 214, and data provider 210 is associatedwith data source 216. In the illustrated and described embodiment, thedata sources can comprise different types of data sources each withtheir own particular access nuances. In addition, indexing mechanism 302includes or otherwise has access to an index of the content contained inthe data sources. Using an indexing mechanism can serve to provideefficiencies in data search and retrieval as will be appreciated by theskilled artisan. Any suitable indexing mechanism can be used an exampleof which is Microsoft's® Search, as well as others.

In operation, application 202 exposes an interface 202 a whichessentially provides a callback interface that can be used to returnsearch results through a Notify( ) method that can be called. Data model204 exposes an interface 204 a that includes various methods that can becalled to conduct searches and return search results. To this end, andin this example, interface 204 a includes a Query( ) method, a Cancel( )method, and a Notify( ) method.

The individual data providers 206, 208, and 210 respectively expose aninterface 206 a, 208 a, and 210 a. The individual interfaces include aQuery( ) method that can be used to query an associated data source. Inaddition, the indexing mechanism includes an interface 302 a thatincludes a Query( ) or similar method that can be called to query one ormore data sources.

When application 202 issues a query, it provides a number of parametersand calls the Query( ) method on the data model 204. By way of exampleand not limitation, such parameters can include one or more of a list ofclass IDs associated with the individual data providers that are desiredto be queried, the subject of the query such as any query text or otherdata that might be utilized in the query, a number of desired results,properties of the data that is to be returned, a sort order or relevancyorder, and/or a data model callback which serves as a pointer tointerface 202 a.

When the data model 204 receives the query, it produces a query ID thatit returns to the application 202. A query ID identifies the query forsubsequent reference by the application. The data model 204 receives thequery and, in turn, ascertains, from the included class IDs, which ofthe data providers are to be queried. The data model 204 then generatesappropriate queries for the data providers and then calls the associatedproviders' Query( ) method. The individual data providers receive thequeries and call the Query( ) method on the indexing mechanism 302 whichthen executes the queries on associated data sources. Query results arethen returned back up through the data providers and data model bycalling the data model's Notify( ) method and passing in a list ofsearch results. In turn, the data model 204 calls the application'sNotify( ) method passing in the returned search results. The applicationcan then use the search results in any suitable way such as bypresenting the search results in a suitable user interface. It is to beappreciated and understood that the returned search results can comefrom one or both of local data sources, such as those illustrated, orremote data sources, such as those shown in FIG. 1.

In this system, the querying/scheduling system is extensible so that newdata providers or new data sources can be easily plugged in. By virtueof exposing a common set of APIs to various applications, the data modelabstracts away the specific nuances that are utilized to access andquery the various data sources. In this manner, applications can accessnew data sources without having to be knowledgeable of the specifics ofhow access takes place. Rather, an associated data provider that isknowledgeable of new data sources can be plugged into the system andused by the data model to access and consume data from an associateddata source. In addition, search efficiencies are enhanced through theuse of an indexing mechanism. Further, the indexing mechanism alsoprovides extensibility in that it does not require a new data providerto add more data sources.

Example Method

FIG. 4 is a flow diagram that illustrates steps in a method inaccordance with one or more embodiments. The method can be implementedin connection with any suitable hardware, software, firmware, orcombination thereof. In the illustrated and described embodiment, themethod can be implemented using systems such as those shown anddescribed above in connection with FIGS. 2 and 3, as well as othersystems described below.

Step 400 issues a search query to a data model. This step can beimplemented in any suitable way. For example, in at least someembodiments, the search query can be generated by an applicationresponsive to some type of user action such as entering search text in asuitable user interface. Alternately or additionally, other types ofuser action can include, by way of example and not limitation, selectingan image or a file such as a multimedia file or a music file. Further,other user actions can include selecting text such as a date or daterange to view history or favorites, selecting a rating to view historyor favorites, selecting a most recently used or most frequently usedoption, and/or selecting a web page snapshot (e.g., a preview) to namejust a few. In one or more embodiments, the search query can be issuedby calling an API exposed by the data model. Step 402 ascertains one ormore data providers identified in the search query. This step can beimplemented in any suitable way. For example, in at least someembodiments, the search query issued by the application can include oneor more parameters that identify associated data providers that are toconduct or otherwise be involved in the search query.

Step 404 issues the search query to one or more identified dataproviders. This step can be implemented in any suitable way such as, forexample, calling a suitably configured API exposed by one or more of thedata providers. Step 406 conducts a query of one or more associated datasources. This step can be implemented in any suitable way. For example,in at least some embodiments, the step can be implemented by a dataprovider executing the particular search query on an associated datasource. Alternately or additionally, this step can be implemented by anindexing mechanism that executes the particular search query on one ormore data sources.

Step 408 returns search results to the data model. This step can beimplemented in any suitable way. For example, a list of search resultscan be returned through the data providers to the data model.Alternately or additionally, search results can be returned directly toan application by a data provider. Step 410 returns the search resultsto a client application that issued the initial query. The applicationcan then make use of the search results in any suitable way. Forexample, in at least some embodiments, the application can displaysearch results for the user, an example of which is provided below.

Example Web Browser Embodiment—Implementation Example

FIG. 5 illustrates an example system in accordance with one embodimentgenerally at 500. In this example, like numerals from the FIG. 3embodiment have been utilized to depict like components. It is to beappreciated and understood, however, that the application of FIG. 5 canbe used in a system such as that described in FIG. 2 above. For the sakeof brevity, the description of FIG. 5's components is not repeated here.

In this particular example, system 500 includes an application in theform of a Web browser 502 having an interface 502 a. Web browser 502includes a user interface or view 504 that is exposed to the user. Inthis example, user interface or view 504 includes one or moreinstrumentalities that can be utilized by a user to spawn a search queryas described above. In this particular example, a user instrumentality506 in the form of an address bar is provided. In operation, as a userenters text into the address bar, a search query is created for theindividual letters that the user enters. In one or more embodiments, auser can also select a start tab page, favorites center or a favoritebar to name just a few. Accordingly, as a user enters their text letterby letter, individual search queries are created and the data model 204is called with each of the individual search queries. Execution of thesearch queries by the data model can be performed as described above inconnection with FIGS. 2 and/or 3.

In the discussion below, an example implementation of the FIG. 5 systemis provided. It is to be appreciated and understood, that the describedimplementation is provided as an example only. Accordingly, othersystems having different implementations can be used without departingfrom the spirit and scope of the claimed subject matter.

In operation, the different data layers that make up system 500, e.g.,the data model, data providers, and indexing mechanism are configured topass up relevant information to the user interface or view 504. The userinterface or view, in turn, is able to report down the data layersparticular actions that the user has taken. For example, if the userclicks “delete”, then the data that has been previously passed downshould be removed. The delete action can remove an underlying dataobject that has been created for a particular search query.

As noted above, a number of different data sources or stores can beused, examples of which are illustrated at 212, 214, and 216. In one ormore embodiments, these data sources can include, by way of example andnot limitation, a typed URL source, a favorites source, a feeds source,a history source, and/or an Internet search providers source.

Typed URLs can be stored, in one or more embodiments, in the system'sregistry. The typed URLs source can include both actual URLs that theuser has typed, as well as local and network resources (e.g. “c:\foo” or“\\server\share”). In one or more embodiments, these different sourcesare treated the same in terms of executing search queries. In one ormore embodiments, a user's default favorites store is used as thefavorites source. Additionally, in one or more embodiments, a defaultfeed store is used as the feeds source. Further, in one or moreembodiments, a user's browser history is used as the history source.Further, in one or more embodiments, third-party search providers canplug into the system's data model so that search queries can beconducted across remotely-located data sources.

Example Data Layer Diagram

FIG. 6 illustrates an example data layer diagram in accordance with oneor more embodiments generally at 600. In this particular example, thedata layer diagram corresponds to the system shown in FIG. 5 andprovides additional information associated with one implementation ofthe FIG. 5 system. In this particular example, the data layer diagramincludes a presentation layer 602, a query and aggregation layer 604, anindexing layer 606, and a storage layer 608.

Within the presentation layer 602, a so-called view layer is provided bythe address bar, search box, and/or other user interface clients (e.g.,a favorites center, a “file.open” dialog, a pop-up blocker picker andthe like, within the Web browser. An example of a view is a drop-downwindow provided by the address bar. The view layer and its variouscomponents can define which data sources to use, how to handle mouse andkeyboard events, how to lay out results and the like. The view layer canalso define the number of elements that it wants to have returned to itfrom the layers below.

The presentation layer's user interface includes two components—a viewcontroller and a data controller. The view controller provides variousview options that the user interface has at its disposal, such as all ofthe various ways to layout results. The data controller provides variousdata options that the view can have. For example, the data controllercan control which data sources are at its disposal. Additionally, thedata controller initiates search queries based on keystrokes and/orother user input and serves as a communication interface with the layersbelow it. Some of the other general responsibilities of the datacontroller are that it initiates the view controller and data model forits use; it can enumerate the various data sources that are available toa particular view; it can receive query results from the data model andformat the results into a user interface view; and, it can cache dataresults to avoid resubmitting data requests when appropriate.

The query and aggregation layer 604 includes the data model and variousdata providers. As indicated above, the data model is responsible fordistributing queries across providers and across threads if so desired.The data model is also responsible for initiating and/or cancelingsearch queries, as well as handling timers and thread limits. In one ormore embodiments, the data model can turn search queries intoappropriate SQL commands, distribute the commands to the data providers,collect results, and/or stop or cancel search requests. The data modelcan, in some embodiments, understand what data sources are available,where the data sources reside, and how to query for each. That is, in atleast some embodiments, data sources can be transparent to the datamodel. In these cases, the data model can receive a class ID associatedwith a data provider object, create the data provider and then query thedata provider. In this case, the data model may not know the type ofdata source it is wrapping or where that data source resides. It maysimply know that the wrapping data provider implements Query( ) and thatit can call Query( ) to perform a query given commonly known query data.In one or more embodiments, the data model supports both synchronous andasynchronous communication.

Data providers are the components that communicate with the actual datasources and/or indexing mechanisms or remote query interfaces. The dataproviders process search queries from the data model and communicate thesearch queries to the appropriate components in the data layer. Inaggregation, the data providers can remove redundant results from thesame list if the result appears multiple times from the same datasource. If, on the other hand, the same result appears from multipledifferent sources, the data providers do not remove the same results.

In one or more embodiments, data providers can have different behaviors.As such, threading properties associated with individual data providerscan be classified into three groups: synchronous, asynchronous, andpersistent. Synchronous threading can be used for data providers thatare fast and wish to be run synchronously. In these instances, the dataproviders are callable on the user interface thread. Some dataproviders, on the other hand, may be somewhat slower or blocking. Inthese instances, asynchronous threading can be used and the number ofthreads that are allocated for their use can be capped. Further, somedata providers will process multiple requests in one instance. In theseinstances, persistent threading or threading which utilizes statebetween requests can be used. For example, data providers associatedwith history, favorites, and/or feeds can utilize asynchronous threadingbecause searching may take a variable amount of time. On the other hand,data providers associated with typed URLs can utilize synchronousthreading because in at least some implementations, typed URLs utilize aregistry lookup and hence, can be processed on the user interfacethread.

Accordingly, and to reduce potential data provider performance impact,the data model can utilize a set of guidelines as follows. First, somedata providers can run on the user interface thread synchronously.Second, some data providers can run on a temporary worker threadallocated from a pool. Third, some data providers can utilize a singleinstance that can service and efficiently process multiple requests.Fourth, a limit can be defined as to the number of threads the datamodel has under its control. This can be done to limit the total numberof threads a data model instance can spin up. Fifth, the number of childthreads that a data provider can create can be limited. This can ensurethat a particular data provider does not utilize all of the threads thata data model can have. Sixth, the number of threads allocated to asingle data provider instance can be limited. This can ensure that everydata provider gets a fair chance to the thread pool and will not beimpacted by other data providers. Seventh, there can be a queue for eachdata provider class that is blocked waiting for threads so that requestsfor a particular data provider are throttled. In addition, the datamodel can employ one or more timers to ensure that time limits are setduring operation. For example, input timers can be used to buffer inputso the system is not slowed down by feeding it too much input tooquickly. For example, typing “Microsoft” may only send “M” as the firstinput, and then “Microsoft” as the second input. The characters in themiddle would be buffered under the input timer. Alternately oradditionally, query timers can provide time out periods to limit theamount of time a data provider takes to query. This can reduce thechances of a malicious data provider taking too long and inefficientlyusing or tying up resources. For example, if it takes more than x amountof time, the query can be killed.

The indexing layer 606 includes one or more indexes as well as anindexing mechanism and a remote query interface. The indexing layer canalso have or use local data providers. For example, typed URLs might bestored on local storage but may not be indexed. The indexing mechanismis used to run searches on the index and return results to anappropriate data provider. The remote query interface is used to querythird-party providers such as third-party search providers.

The storage layer 608 can, but need not, include different protocolhandlers which are responsible for populating the index of indexinglayer 606. Individual protocol handlers are associated with differentdata sources such as the illustrated favorites source, history source,and RSS source. The individual protocol handlers populate the index withdata from their associated data source. The storage layer also includesvarious data sources or data stores which store the actual data. ForRSS, favorites, and history, data is stored in a native format and thedata model does not deal directly with this layer. Rather, the datamodel assumes that the indexing layer pulls the relevant data out of thenative stores and into the index.

Having described some examples systems and an implementation example,consider now an example system that can be utilized to implement one ormore of the above-described embodiments.

Example System

FIG. 7 illustrates an example computing device 700 that can implementthe various embodiments described above. Computing device 700 can be,for example, computing device 102 of FIG. 1 or any other suitablecomputing device.

Computing device 700 includes one or more processors or processing units702, one or more memory and/or storage components 704, one or moreinput/output (I/O) devices 706, and a bus 708 that allows the variouscomponents and devices to communicate with one another. Bus 708represents one or more of any of several types of bus structures,including a memory bus or memory controller, a peripheral bus, anaccelerated graphics port, and a processor or local bus using any of avariety of bus architectures. Bus 708 can include wired and/or wirelessbuses.

Memory/storage component 704 represents one or more computer storagemedia. Component 704 can include volatile media (such as random accessmemory (RAM)) and/or nonvolatile media (such as read only memory (ROM),Flash memory, optical disks, magnetic disks, and so forth). Component704 can include fixed media (e.g., RAM, ROM, a fixed hard drive, etc.)as well as removable media (e.g., a Flash memory drive, a removable harddrive, an optical disk, and so forth).

One or more input/output devices 706 allow a user to enter commands andinformation to computing device 700, and also allow information to bepresented to the user and/or other components or devices. Examples ofinput devices include a keyboard, a cursor control device (e.g., amouse), a microphone, a scanner, and so forth. Examples of outputdevices include a display device (e.g., a monitor or projector),speakers, a printer, a network card, and so forth.

Various techniques may be described herein in the general context ofsoftware or program modules. Generally, software includes routines,programs, objects, components, data structures, and so forth thatperform particular tasks or implement particular abstract data types. Animplementation of these modules and techniques may be stored on ortransmitted across some form of computer readable media. Computerreadable media can be any available medium or media that can be accessedby a computing device. By way of example, and not limitation, computerreadable media may comprise “computer storage media”.

“Computer storage media” include volatile and non-volatile, removableand non-removable media implemented in any method or technology forstorage of information such as computer readable instructions, datastructures, program modules, or other data. Computer storage mediainclude, but are not limited to, RAM, ROM, EEPROM, flash memory or othermemory technology, CD-ROM, digital versatile disks (DVD) or otheroptical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or any other medium which canbe used to store the desired information and which can be accessed by acomputer.

CONCLUSION

Various embodiments provide an independent layer between an applicationuser interface and various data sources so that both the user interfaceand data sources can be added, removed, or modified without affectingthe other. The independent layer provides scalability to allow datasources and data providers to be plugged into a system in an easymanner.

In one or more embodiments, the independent layer provides a common setof query APIs that can be used by client applications to make queries onone or more data sources. The independent layer then communicates thequeries to one or more data providers associated with individual datasources. Queries are executed on the data sources and results arereturned back up through the data providers and independent layer forconsumption by a client application. In at least some embodiments, theclient application comprises a Web browser that makes use of theindependent layer.

Although the subject matter has been described in language specific tostructural features and/or methodological acts, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

What is claimed is:
 1. A method comprising: presenting a common accessmechanism that can be used by one or more applications to accessdifferent data sources in a storage layer and have data stored in thedata sources returned to the one or more applications, the common accessmechanism being presented by a data model that is implemented by a queryand aggregation layer of an extensible querying/scheduling system, atleast some individual data sources being configured to store data indifferent formats and have their own specific access mechanisms of whichthe one or more applications are unaware; and creating, by the datamodel, one or more data providers that are individually associated withindividual data sources and knowledgeable of how to access data storedin an associated data source, at least some of the one or more dataproviders being configured to receive queries for data and execute thequeries using a different thread than the data model, at least some ofthe one or more data providers being creatable on a thread that is asame thread as the data model.
 2. The method as recited in claim 1,wherein the query and aggregation layer is configured to becommunicatively coupled to, and independent of, a presentation layer andthe storage layer of the extensible querying/scheduling system.
 3. Themethod as recited in claim 1, wherein the one or more applicationscomprise a Web browser application.
 4. The method as recited in claim 1,further comprising using the one or more data providers to query one ormore associated data sources using one or more query methods, at leastsome of the query methods being different than a common query methodused by the data model to query the one or more data providers.
 5. Themethod as recited in claim 1, wherein the different data sourcescomprise both local data sources and remote data sources.